Do you have the original remote?
Try pulling up the "Factory Reset " menu with the remote. This reset is differnt from the button reset on the front. Mine was a Mitsu WD-52628 and it responded to "Menu 1,2,3" for this default reset. I was looking in the wrong places like everyone here. I replaced the lamp and the green light started. Same as everyone else. I think it may have to do with putting the new lamp in. Everything has to be reset to factory specs with a new lamp.
Try this and post your results please.